# Ureteroscopy and lasertripsy for lower pole stones <2 cm, in situ vs displacement? A systematic review and meta‐analysis

## TL;DR

This study compares two methods for treating kidney stones and finds that moving the stone improves success rates without increasing complications.

## Contribution

The study provides a meta-analysis showing displacement improves stone-free rates for lower pole stones <2 cm.

## Key findings

- Displacement strategies significantly increase stone-free rates compared to in situ treatment.
- There is no significant difference in complication rates between the two methods.
- Displacement requires slightly longer operative time, but the difference is not clinically significant.

## Abstract

To investigate the outcomes of ureteroscopy and lasertripsy in lower pole renal stones <2 cm when treated in situ compared to displacement to the upper pole.

Using the Medical Literature Analysis and Retrieval System Online (MEDLINE)/PubMed, the Excerpta Medica dataBASE (EMBASE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Cochrane Library, and Clinicaltrials.gov we identified adult population, English language, studies published until March 2023 comparing surgical outcomes and stone‐free rates (SFRs) in relation to lower pole stones <2 cm managed in situ vs those displaced (International Prospective Register of Systematic Reviews [PROSPERO] identifier: CRD42023432750). Analysis was performed using R with the ‘meta’ package. Bias analysis was performed using the Cochrane Risk of Bias 2 tool for randomised trials and the Newcastle–Ottawa scale for observational studies. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was used to ascertain the certainty of evidence.

A total of five studies were included, comprising two retrospective cohort studies, three randomised trials, with a total of 408 patients. Meta‐analysis demonstrated SFRs are significantly higher in those patients undergoing displacement vs those managed in situ (risk ratio 1.21, 95% confidence interval [CI] 1.10–1.34, P < 0.001). There was no significant difference in complication rates. Operative time was significantly longer in the displacement group (mean difference 5.62 min, 95% CI 0.40–10.83 min; P = 0.03). Overall risk of bias was moderate. Certainty of evidence was moderate for stone‐free status, and very low for all other outcomes.

This systematic review and meta‐analysis demonstrates that for lower pole stones <2 cm displacement strategies have significantly higher SFRs than treatment in situ, with no significant difference in complications. There is significantly increased operative time in the displaced group, but an additional 6 min is unlikely to be clinically significant.